Airbag cushion with vent tube

ABSTRACT

An airbag module comprising a housing with an inflatable airbag cushion disposed therein and at least one vent tube attached to the inflatable airbag cushion, wherein during inflatable airbag cushion deployment with an obstruction, the at least one vent tube remains open, and during inflatable airbag cushion deployment without an obstruction, the at least one vent tube at least partially closes.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No. 11/786,559, titled Airbag Vent Tube, filed Apr. 12, 2007. U.S. application Ser. No. 11/786,559 is incorporated herein by specific reference.

TECHNICAL FIELD

The present invention relates generally to the field of automotive protective systems. More specifically, the present invention relates to inflatable airbags for automobiles.

BRIEF DESCRIPTION OF THE DRAWINGS

Understanding that drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings as listed below.

FIG. 1 is a schematic view of an airbag module.

FIG. 2 is a schematic view of an airbag module.

FIG. 3 is a side view of an airbag module.

FIG. 4A is a cross-sectional view of an airbag module.

FIG. 4B is a cross-sectional view of a partially deployed airbag module.

FIG. 4C is a cross-sectional view of a fully deployed airbag module.

FIG. 4D is a cross-sectional view of a fully deployed airbag module with tethered vent tubes.

FIGS. 5A-5C show the deployment of an airbag module with a normally positioned occupant.

FIGS. 6A-6C show the deployment of another embodiment of an airbag module with an out-of-position occupant.

FIG. 7A is a cross-sectional view of another embodiment of an airbag module.

FIG. 7B is a close up cross-sectional view of a portion of the airbag module shown in FIG. 7A.

FIG. 8A is a cross-sectional view of another embodiment of an airbag module.

FIG. 8B is a close up cross-sectional view of a portion of the airbag module shown in FIG. 8A.

INDEX OF ELEMENTS IDENTIFIED IN THE DRAWINGS

-   -   100 airbag module     -   110 airbag module housing     -   115 inflator     -   120 diffuser     -   130 housing opening     -   200 airbag cushion     -   230 vent tube     -   234 vent tube exit     -   300 airbag cushion     -   310 airbag module housing     -   313 housing opening     -   315 inflator     -   320 diffuser     -   330 vent tube     -   335 tether     -   400 airbag cushion     -   410 airbag module housing     -   430 vent tube     -   490 occupant     -   500 airbag module     -   501 airbag cushion     -   502 cushion aperture     -   510 airbag housing     -   513 housing opening     -   515 inflator     -   520 diffuser     -   530 vent tube     -   531 vent body     -   532 vent rim     -   533 vent base     -   534 vent aperture     -   536 base aperture     -   540 vent protrusion stop     -   541 ring portion of stop     -   542 aperture of stop     -   545 attachment     -   600 airbag module     -   601 airbag cushion     -   610 airbag housing     -   613 housing opening     -   615 inflator     -   620 diffuser     -   622 attachment tab     -   630 vent tube     -   633 vent base     -   650 releasable attachment     -   655 seam

DETAILED DESCRIPTION

Described below are embodiments of a motor vehicle airbag module and airbag cushion vent tube. As those of skill in the art will appreciate, the principles of the invention may be applied to and used with a variety of airbag deployment systems including frontal driver and passenger airbags, knee airbags, overhead airbags, curtain airbags, and the like. Thus, the present invention is applicable to vehicle airbag cushions of various shapes and sizes.

Airbag cushions are frequently located in an instrument panel and directly in front of an occupant. During a collision, an airbag cushion inflates and deploys through a cosmetic cover. The airbag cushion deploys towards the occupant and provides a restraint.

Full inflation of an airbag is not always desired when there is an obstruction in the path of deployment such as when an occupant is near or out of position relative to the airbag cover. An out-of-position occupant may experience punch-out forces when the airbag initially breaks through the cover and deploys into the near or out-of-position occupant. In such cases, partial airbag inflation may offer optimal protection. For example, partial airbag inflation may be desired when the occupant being protected by the airbag cushion is a child, a baby in a rear facing car seat or an adult positioned too close to the air bag cushion. Embodiments described below include vehicle airbag systems that respond to an occupant's position and control the airbag cushion inflation to avoid excessive punch-out and deployment forces.

With reference now to the accompanying figures, particular embodiments of the invention will now be described in greater detail. FIG. 1 is a perspective view which shows an airbag module 100 which can include a module housing 110 and an inflator 115 configured to deliver gas into an airbag cushion such as the airbag cushion 200 shown in FIG. 2. The airbag cushion 200 may include at least one vent tube, such as vent tubes 230. Gas may enter the interior of the airbag cushion 200 through the inflator 115 and completely inflate the airbag cushion 200 during deployment. The gas may also exit the interior of the airbag cushion 200 through vent tubes 230 during deployment and if complete inflation of the airbag cushion 200 is not desired.

One or more vent tubes, such as vent tubes 230, may be located where desired on the airbag cushion 200. The diameter of the vent tubes 230 can be adjusted by controlling the area of the opening at the vent tube exit 234. For example, the area of the opening at the vent tube exit 234 may be sewn or bonded to adjust the size of the opening. The location of a vent tube on the airbag cushion 200 may depend on the airbag module deployment angle, vehicle interior geometry, and cushion fold type. For example, vent tubes 230 may be located on the side, top, bottom, or rear of the airbag cushion 200. The size and length of the vent tubes 230 may be modified as desired and adjusted to control and optimize venting and closing during airbag deployment. The vent tubes 230 may be attached to the airbag cushion 200 by any appropriate method such as by sewing, stapling, or using an adhesive. The vent tubes 230 may also be integral to the airbag cushion 200.

With continued reference to FIG. 1 and FIG. 2, the airbag module 100 may include a module housing 110 configured with one or more housing openings such as housing openings 130 configured to be aligned with the vent tubes 230 and allow the vent tubes 230 to vent inflation gas through the housing openings 130 during airbag deployment. In one embodiment, the alignment of the vent tubes 230 with the housing openings 130 may be controlled by cinching the vent tubes 230 after the airbag cushion 200 has been folded (not shown). The vent tubes 230 may extend through the housing openings 130 and beyond the module housing 110 before deployment and during deployment.

Referring to FIG. 3, the airbag module 100 may also include a diffuser such as diffuser 120 configured to direct the inflation gas toward the vent tubes 230 during airbag inflation. More particularly, a loop diffuser may be sewn inside the airbag cushion 200. Alternatively, the module housing 110 can include a housing diffuser. The diffuser 120 may be attached to the airbag cushion 200 or disposed on the module housing 110. The diffuser may be rectangular, trapezoidal, hexagonal, round, etc. It may also have a portion which is round or elliptical while other portions are angled.

If a vehicle occupant is in a normal position and airbag inflation is unrestricted, diffuser 120 functions to direct at least a portion of the inflation gas generally toward the vent tube(s). However, because diffuser 120 and vent tubes 230 are independent of each other, the airbag cushion side panels can expand and move during inflation such that the inflation gas flow becomes misaligned with the vent tubes 230. In this way, the vent tubes 230 may be closed as the airbag cushion fully expands thus, retaining gas for normal occupant restraint.

FIGS. 4A-4C provide a cross-sectional view of an airbag cushion 300 deploying from a module housing 310. For illustrative purposes, multiple vent tubes 330 are shown in FIGS. 4A-4C, however one or more vent tubes may be used to vent the inflation gas from the airbag cushion 300. In FIG. 4A, the initially deploying airbag cushion 300 may include vent tubes 330 symmetrically attached and extending out of the module housing 310 at housing openings 313. In the undeployed state, the airbag cushion 300 may be folded within the module housing 310 and may include areas of slack both above and below the vent tubes 330 as shown by FIG. 4A. Upon initial deployment of the airbag cushion 300, the inflation gasses, represented by the arrows, are generated by the inflator 315 and may flow out of the diffuser 320 and into the airbag cushion 300 and out of the vent tubes 330.

As shown by FIG. 4B, as the inflation gasses begin to fill the airbag cushion 300, the folds above the vent tubes 330 begin to expand allowing the airbag cushion 300 to deploy beyond the module housing 310. At this time, the vent tubes 330 are still open and the inflation gasses may exit the vent tubes 330. If the airbag cushion 300 does not encounter any obstruction during deployment, it may fully inflate as illustrated by FIG. 4C.

With continued reference to FIG. 4C, as the airbag cushion 300 nears full inflation, the folds in the fabric both above and below the vent tubes 330 may have been removed and the tension of the inflating airbag cushion 300 may place the vent tubes 330 out of alignment with the housing openings 313. As the vent tubes 330 are moved out of alignment with the housing openings 313 they may be pulled through the housing openings 313 at an angle thereby obstructing the exit of the inflation gases out of the at least partially closed vent tubes 330. The obstruction of the vent tubes 330 may allow the inflation gasses to fully inflate the airbag cushion 300 and provide the optimal protection for a properly positioned occupant. In another embodiment shown by FIG. 4D, the vent tubes 330 may be tethered to the airbag cushion 300 such that as the airbag cushion 300 nears full inflation the tension of the inflating airbag will tighten the tethers and cause the vent tubes 330 to be withdrawn from the housing openings 313 and pulled closed. With continued reference to FIG. 4D, tethers 335 may be attached to the vent tubes 330 and to the internal surface of the airbag cushion 300. When the airbag cushion 300 is in the undeployed or partially deployed state, the tethers 335 would be slack within the airbag leaving the vent tubes 330 open for the exit of inflation gasses. However, when the airbag cushion 300 is fully inflated, the expansion of the pressure of the inflation gasses against the internal surface of the airbag cushion 300 may tighten the tethers 335 and cause the vent tubes 330 to be at least partially closed under the tension from the tethers 335.

FIGS. 5A-5C illustrate yet another embodiment showing the inflation of a deploying airbag cushion 400 without obstruction in the deploying path. The depicted airbag module housing 410 may include an airbag cushion 400 comprising two vent tubes 430 symmetrically disposed on the airbag cushion 400. Additional vents (not shown) may be optional in certain airbag cushion embodiments based on venting requirements. The location and number of vent tubes 430 may vary according to design and function. An occupant 490 is in a normal seating position which will allow the airbag cushion 400 to fully expand before impacting the occupant. In this manner, the occupant 490 benefits from the full restraint capability of the airbag cushion 400.

In FIG. 5A, the initial breakout of the airbag cushion 400 occurs. The vent tubes 430 are open and, in the depicted embodiment, extend from the airbag cushion 400 and through the airbag module housing 410. In FIG. 5B, the vent tubes 430 are slightly (as shown), or fully withdrawn from the airbag module housing 410, partially closing the vent tubes 430 and restricting gas flow through the vent tubes 430. Vent tubes 430 may also be closed from within the interior of the airbag cushion 400 (not shown). In FIG. 5C, vent tubes 430 are completely closed and normal restraint is provided to the occupant 490.

FIGS. 6A-6C illustrate the inflation of a deploying airbag cushion 400 with obstruction in the deploying path. An occupant 490 may be out-of-position and obstruct the deploying airbag cushion 400 and prevent the airbag cushion 400 from fully inflating. In FIG. 6A, airbag cushion 400 begins initial deployment as in FIG. 5A. In FIG. 6B, airbag cushion 400 impacts the occupant 490 and the vent tubes 430 remain open and venting of the inflation gas occurs from the vent tubes 430. The inflation of airbag cushion 400 is restricted and the occupant 490 receives less than the full deployment force of the airbag cushion 400. In this way, potential injury to an out-of-position passenger from the initial punch-out forces of an inflatable airbag may be avoided. In FIG. 6C, cushion 400 is partially inflated and provides limited restraint while venting may continue through vent tubes 430.

FIGS. 7A and 7B are cross-sectional views of another embodiment of an airbag module 500. Airbag module 500 is configured to provide a softer cushion for out of position occupants and also provide sufficient cushioning for normally positioned occupants. Airbag module 500 may comprise an inflatable airbag cushion 501, a housing 510, an inflator 515, a diffuser 520, at least one vent tube 530, and at least one vent protrusion stop 540. Airbag module 500 and its components may be configured similarly to and may function similarly as airbag modules and airbag module components described previously herein, except where the following description of airbag module 500 and its components varies from those previously described. Airbag cushion 501 is anchored to housing 510 and is configured to be inflated by inflator 515 upon detection of predetermined conditions. Diffuser 520 is configured to receive inflation gas from inflator 515 and at least partially redirect the inflation gas in the direction of at least one closeable vent 530.

Airbag housing 510 may comprise at least one opening 513 which is configured to receive a vent tube 530. Airbag cushion 501 may comprise at least one cushion aperture 502 over which a closeable vent tube 530 is disposed. Vent tube 530 may comprise a body portion 531, a rim 532, a base portion 533, a vent aperture 534, and a base aperture 536. FIGS. 7A and 7B depict assembly 500 in a packaged configuration or during early airbag cushion 501 deployment, wherein vent 530 body portion 531 protrudes through housing opening 513. As with vent tubes 230, 330, and 430 described herein, vent tube 530 is configured to remain open in case of airbag 501 deployment with obstruction and become closed in case of airbag deployment without obstruction. During manufacture, assembly, or packaging of airbag module 500, a worker pulls vent tubes 530 through housing openings 513. To reduce variation in the amount of vent tube 530 that is pulled through housing opening 513, at least one vent tube protrusion stop 540 is employed. Protrusion stop 540 assures that no more than a predetermined amount of vent tube 530 protrudes through housing opening 513.

As best seen in FIG. 7B, body portion 531 defines a tubular structure that has a lumen, wherein the lumen has vent aperture 534 at one end and base aperture 536 at the other. Base aperture 536 is at least partially defined by vent base 533 and is at least partially aligned with cushion aperture 502. Body portion 531 defines rim 532, which defines vent aperture 534. In the depicted embodiment, protrusion stop 540 comprises a circular washer-shaped piece manufactured from plastic that has an aperture 541 and a ring portion 542. Aperture 541 of protrusion stop 540 at least partially circumnavigates cushion aperture 502 and vent base aperture 536. Ring portion 542 of protrusion stop 540 may abut an inner surface of housing 510 and thereby limit further protrusion of vent tube 530 through housing aperture 513. Protrusion stop 540 may be fixedly attached to cushion 501 and vent 530 via an attachment 545, which may comprise stitching, wherein the stitching pierces the protrusion stop. Further, attachment 545 may also couple vent 530 to cushion 501. In alternative embodiments, protrusion stop 540 may comprise any suitable shape of any suitable piece of rigid or semi-rigid substance such as plastic or fabric. During manufacture vent tube 530 can be pulled through housing opening 513 and away from housing 510 until ring portion 542 of protrusion stop 540 contacts an inner face of the housing.

As will be appreciated by those skilled in the art, a variety of types and configurations of tube vent/airbag cushion junctions and attachments can be utilized without departing from the scope and spirit of the present invention. For example, in one embodiment, the tube vent comprises a contiguous extension of the airbag cushion such that the junction between them does not comprise any sort of attachment. In another embodiment, the base portion of the vent tube is disposed on the inside of the airbag cushion rather than on the outside as depicted in FIG. 7B. In alternative embodiments, the vent tube and the airbag cushion are coupled using adhesive, ultrasonic welds, or heat fusion.

As will be appreciated by those skilled in the art, a variety of types and configurations of protrusion stops and techniques for coupling a protrusion stop to a vent and/or airbag cushion can be utilized without departing from the scope and spirit of the present invention. For example, in one embodiment, the protrusion stop is not disposed between layers of vent tube and airbag cushion material, but rather is disposed on the outside of the of the vent tube and cushion junction. In another embodiment, the protrusion stop is glued to the cushion using adhesive. In alternative embodiments, the protrusion stop is disposed within a pocket formed by the base portion of the vent; the junction of the vent tube and the cushion; by the cushion alone; or by a different piece of material coupled to the cushion. In other alternative embodiments the protrusion stop comprises one or more apertures, which are employed to couple protrusion stop to the vent, the cushion, or a combination of the vent and the cushion. In another embodiment a plurality of protrusion stops is employed for each vent tube.

FIGS. 8A and 8B are a cross-sectional views of another embodiment of an airbag module 600, wherein the module comprises an inflatable airbag cushion 601, a housing 610, an inflator 615, a diffuser 620, and at least one vent tube 630. Airbag module 600 and its components may be configured similarly to and may function similarly as airbag modules and airbag module components described previously herein, except where the following description of airbag module 600 and its components varies from those previously described.

Vent tubes 630 may comprise a separate piece of fabric that has a body portion 631 that extends to a base portion 633. Body portion 631 can protrude through holes 613 in housing 610, and base portion 633 may be coupled to cushion 601 via a seam 655. Seam 655 may be formed by stitches, adhesive, ultrasonic welding, or heat fusion. Diffuser 620 may also be coupled to vent tubes 630 and cushion 601 via a releasable attachment 650.

As noted for module 500, during manufacture, assembly, or packaging of airbag module 600, a worker pulls vent tubes 630 through housing openings 613. To help assure that no more than a predetermined amount of vent tube 630 protrudes through housing opening 613, the vent tubes are releasably coupled to diffuser 620 at attachment tabs 622 (best seen in FIG. 8B). The releasable coupling of vent tubes 630 to diffuser 620 also helps to reduce variation between airbag modules 600 in the extent to which the vent tubes protrude through vent openings 613. If vent-coupled diffuser 620 is approximately centered within housing 610, no more than a predetermined length of vent tubes 630 may protrude from the housing. During airbag 601 deployment releasable attachment 650, which may comprise tear stitching or any other suitable releasable attachment, is configured to allow diffuser 620 to become uncoupled from vent tube 630.

Various embodiments for vent tubes have been disclosed herein. The vent tubes disclosed herein are examples of means for venting gas out of the airbag during deployment. The vent tubes in combination with the housing openings are examples of venting means for airbag deployment without obstruction and enabling the venting means to remain open upon airbag deployment with obstruction. The diffusers disclosed herein are examples of means for diffusing gas by re-directing inflation gas to the venting means from an inflator such that the gas exits the inflatable airbag cushion by way of the venting means when deployment of the airbag is obstructed. The vent protrusion stop 540 and the vent-coupled diffuser 620 disclosed herein are examples of means for limiting the protrusion of a vent tube through a housing opening.

Without further elaboration, it is believed that one skilled in the art can use the preceding description to utilize the present disclosure to its fullest extent. The examples and embodiments disclosed herein are to be construed as merely illustrative and not a limitation of the scope of the present disclosure in any way. It will be apparent to those having skill in the art that changes may be made to the details of the above-described embodiments without departing from the underlying principles of the disclosure described herein. In other words, various modifications and improvements of the embodiments specifically disclosed in the description above are within the scope of the appended claims. Note that elements recited in means-plus-function format are intended to be construed in accordance with 35 U.S.C. §112 ¶6. The scope of the invention is therefore defined by the following claims. 

1. An airbag module, comprising: an airbag module housing, wherein the airbag module housing comprises at least one housing opening; an inflatable airbag cushion disposed inside the airbag module housing, at least one vent tube protruding outwardly through the housing opening such that the at least one vent tube is open and can move relative to the at least one housing opening; a protrusion stop coupled to the at least one vent tube and the inflatable airbag cushion, wherein the protrusion stop is positioned to engage an inner surface of the airbag module housing around the housing opening to limit the outward protrusion of the vent tube through the at least one housing opening and prevent more than a predetermined amount of the vent tube from protruding through the housing opening during and after packaging of the inflatable airbag cushion and prior to deployment of the inflatable airbag cushion; whereby during deployment of the inflatable airbag cushion with obstruction, the at least one vent tube remains open, continues to extend outwardly through the at least one housing opening, and vent inflation gas; and during inflatable airbag cushion deployment without obstruction, inflation gas causes the inflatable airbag cushion to become tensioned to inwardly null at least a section of the at least one vent tube through the at least one housing opening and against the one housing opening so that the at least one vent tube at least partially closes.
 2. The airbag module of claim 1, further comprising at least one diffuser configured to re-direct inflation gas to the at least one vent tube from an inflator.
 3. The airbag module of claim 2, wherein the at least one diffuser is configured to re-direct inflation gas to the at least one vent tube from the inflator such that the gas exits the inflatable airbag cushion by way of the at least one vent tube when deployment of the inflatable airbag cushion is obstructed.
 4. The airbag module of claim 2, wherein the at least one diffuser is attached to the inflatable airbag cushion.
 5. The airbag module of claim 1, wherein the protrusion stop comprises a piece of semi-flexible plastic material that is coupled to the at least one vent tube via stitching.
 6. The airbag module of claim 1, wherein the protrusion stop is between the at least one vent tube and the inflatable airbag cushion.
 7. The airbag module of claim 1, wherein the protrusion stop comprises a rigid material that is coupled to a base portion of the vent tube.
 8. The airbag module of claim 1, wherein the protrusion stop comprises a washer shaped niece that is substantially circular and comprises an aperture.
 9. The airbag module of claim 1, wherein the at least one vent tube is integral to the inflatable airbag cushion.
 10. The airbag module of claim 1, wherein the at least one vent tube comprises two vent tubes attached to the inflatable airbag cushion.
 11. An airbag module, comprising: an airbag module housing comprising at least one housing opening; an inflatable airbag cushion disposed within the airbag module housing; at least one vent tube attached to the inflatable airbag cushion and configured to extend from inside the airbag module housing and through the at least one housing opening and protrude outside of the airbag module housing; at least one member coupled to the vent tube such that when the vent tube protrudes through the opening in the housing up to and including a predetermined distance, the member is stopped by an interior surface of the housing such that further protrusion of the tube vent through the opening is limited; at least one diffuser disposed within the inflatable airbag cushion configured to re-direct inflation gas to the at least one vent tube from an inflator such that the gas exits the inflatable airbag cushion by way of the at least one vent tube when deployment of the airbag is obstructed; wherein during deployment of the inflatable airbag cushion with obstruction, the at least one vent tube remains open; and wherein during inflatable airbag cushion deployment without obstruction, the at least one vent tube at least partially closes as the inflatable airbag cushion fully expands during deployment.
 12. The airbag module of claim 11, wherein the member comprises a piece of semi-flexible plastic material that is coupled to a base portion of the tube vent via stitching.
 13. The airbag module of claim 11, wherein the member comprises a rigid material that is coupled to a base portion of the tube vent.
 14. The airbag module of claim 11, wherein the member comprises a washer shape such that the member is substantially circular and comprises an aperture.
 15. The airbag module of claim 11, wherein the member is disposed between the vent tube and the airbag cushion and circumnavigates an aperture in the airbag cushion.
 16. The airbag module of claim 11, wherein the diffuser is releasably coupled to the vent tube such that when a worker pulls the vent tube through the housing opening during airbag cushion packaging, the vent tube does not protrude through the housing opening beyond a predetermined distance, and wherein upon airbag cushion deployment, the diffuser becomes uncoupled from the vent tube.
 17. The airbag module of claim 11, further comprising: at least one tether attached to the at least one vent tube, wherein the tether is configured to pull the at least one vent tube inside the housing opening during deployment of the inflatable airbag cushion without obstruction.
 18. The airbag module of claim 17, wherein a first end of the at least one tether is attached to the at least one vent tube and a second end of the at least one tether is attached to the interior surface of the inflatable airbag cushion.
 19. An airbag module, comprising: an airbag module housing, wherein the airbag module housing comprises at least one housing opening; an inflatable airbag cushion disposed inside the airbag module housing; at least one vent tube protruding outwardly through the housing opening such that the at least one vent tube is open and can move relative to the at least one housing opening; wherein the outward protrusion of the vent tube through the at least one housing opening is limited such that no more than a predetermined amount of the vent tube protrudes through the housing opening during and after packaging of the inflatable airbag cushion and prior to deployment of the inflatable airbag cushion; whereby during deployment of the inflatable airbag cushion with obstruction, the at least one vent tube remains open, continues to extend outwardly through the at least one housing opening, and vent inflation gas; and during inflatable airbag cushion deployment without obstruction, inflation gas causes the inflatable airbag cushion to become tensioned to inwardly pull at least a section of the at least one vent tube through the at least one housing opening and against the one housing opening so that the at least one vent tube at least partially closes.
 20. The airbag module of claim 19, further comprising at least one diffuser disposed within the inflatable airbag cushion to re-direct inflation gas to the at least one vent tube from an inflator such that the gas exits the inflatable airbag cushion by way of the at least one vent tube when deployment of the airbag is obstructed.
 21. The airbag module of claim 20, wherein the diffuser is attached to the at least one vent tube and is positioned to limit the outward protrusion of the vent tube through the at least one housing opening and prevent more than a predetermined amount of the vent tube from protruding through the housing opening during and after packaging of the inflatable airbag cushion and prior to deployment of the inflatable airbag cushion.
 22. The airbag module of claim 21, wherein the diffuser is releasably coupled to the vent tube such that upon airbag cushion deployment the diffuser becomes uncoupled from the at least one vent tube.
 23. The airbag module of claim 20, wherein the at least one diffuser is attached to the inflatable airbag cushion.
 24. The airbag module of claim 20, wherein the at least one vent tube is integral to the inflatable airbag cushion.
 25. The airbag module of claim 20, wherein the at least one vent tube and the inflatable airbag cushion are not integral. 